Fluid pump



Patented Aug. ze, 194i UNITED STATES.. PATENT OFFICE FLUID PUMP Harold Nilsen, Wayzata, Minn., assignor to George H. lache, Milwaukee, Wis.4

Application March 4, 1940, Serial No. 322,078 Claims. (Cl. 10a-41) `This invention relates to new and useful im'- provements in fluid pumps, generally, and more particularly to such a device which readily lends ,itself for use in connection with hydraulic jacks and other structures wherein a ram or plunger 5 is mounted for reciprocal movement to engage a load or other member to be actuated.

,An object of the present invention is to -provide a fluid pump comprising comparatively few parts, all of which are arranged in" axial alinel0 ment, whereby the operation of assembling the parts is greatly facilitated.

A further object is to provide a ,iiuid pump comprising a cylinder and a piston having an elongated tubular member associated therewith and functioning as acheck valve to prevent return iiow of the iluid fromthe cylinder to the source of iluid supply, when the piston is moved in a direction to force the fluid from the cylinder or tubular member through a discharge port to a device to be operated.

A further object is to provide a iiuid pump comprising a cylinder having a sleeve member mounted therein forv limited sliding movement,

and c. piston being mounted within the sieeve 2 member adapted to pump fluid from a reservoir into the sleeve, when thepiston is moved in one direction, and saidv sleeve member being adapted to be moved into engagement with a seat to prel vent return now of the duid to the reservoir, when 30 the piston is moved in a direction to force the iiuid from the interior of the sleeve member through a discharge port to the device to be operated.

A further object is to provide a iiuld pump comprising a cylinder having an intake connecting it to a source o! fluid supply or a reservoir and having a discharge opening provided with a v.suitable check valve, and a sleeve member being ntied'wiuun inc cylinder and adapted for, limited 4 sliding movement therein, said sleeve member having a conical end adapted to engage a seat surrounding the discharge opening, and said conical end being provided with a central opening.

and a piston being mounted for reciprocal move- 5 ment within the sleeve member and having one end projecting from the'apparatus to facilitate operating it, saidsleeve member being adapted,

upon movement of the piston in lone direction, to move outof engagement'with said seat, whereby tluid is drawn from the reservoir into the interior fofk the sleeve member through, the opening provided at one endl thereof, and said sleeve member beingadapted to be movedintoengagement with u ysaid seat,wlien the piston is moved in the oppo a site direction, whereby the iiuid drawn into the sleeve member is -forced through the opening in said sleeve mem-ber and through the discharge opening of the cylinder to thedevice to be operated. l

` Other objects of the invention reside in the provision of a iiuid pump comprising a sleeve member which, in effect, serves as a cylinder and check valve, and a piston being operable within 4 the sleeve member and having a stem secured to one end thereof adapted to be moved into engagement with a check valve provided in the discharge opemng of the pump, whereby when the piston is moved downwardly to av predetermined position, the check valve is'opened, and the sleeve member may then be positioned to permit the pumped iluid to return through the discharge y opening and intake of the pump to the reservoir or source of iiuid supply; in the provision of an apparatus of theclass described, comprising a cylinder having an intake and a discharge, and a suitable spring-actuated-check valve being provided in the discharge opening, and a sleeve member being mounted within the cylinder, which is movable by fluid pressure into engagement with a seat. thereby to prevent return ow of the nuid to the reservoir; when the piston is moved-in amay be made within the scope of the claims which follow.

Inthejdrawing: Y A Figure is 'an elevational view, partiallyin section, showing the invention -applied to a hydraulic'jack', the pump piston being shown as `when drawing iiuid from the yreservoir into the ,sleeve memberz- Y i v Figure 2 isV avie' showing the' position of the sleeve member,r when the piston is jm'oved' in a direction to fluid through the discharge Figure sis'a view on an enlarged scale, Iiiliowi. u, Whitlei. *ed

also showing the stem on the piston engaged with the check valve in the discharge passage; and

Figure 4 is a view similar to Figure 3, but showing the piston ,and sleeve member partially retracted, or elevated, whereby it will be noted that the check valve and sleeve member are disenof the cylinder or tubular member 4 is'spacedfrom the wall o! the casing 3 to provide an annular uid chamber or reservoir 1, as clearly illustrated in Figure 1. The structure -above described, forms no part of the present invention, and is shown mereLv for illustrative purposes, and it is therefore thought 'necessary to further describe the same in detail. l

An important feature of the present invention resides in the provision of a novel pump,

ing means for circulating duid to and from the lower end of the cylinder 4 to control the operation of the ram or plunger 5. The means provided for thus circulating lthe fluid to and from the cylinder 4, is shown comprising a cylinder 3, shown secured to the casing 3. For convenience, it may be integrally formed therewith, as shown in Figure 1, but it is to be understood that the cylinder 3 and its associated parts may be formed independently of the jack or casing 3, without departing from the scope of the invention.

A sleeve member 3 is tted within the cylinder 3 and has a conical end portion II adapted to engage a seat I2 provided directly therebeneath. An intake port I3 connects the reservoir 1 with the cylinder 3, and a discharge passage I4 leadsA from the bottom of the` cylinder 3 to `a passage Il which, as shown in Figure 1, may establish communication between the discharge e I4 and a chamber I3, provided at the lower end of the Jack cylinder 4. A suitable spring-actuated check valve Il is provided in the discharge passage I4.

A suitable piston I3 is mounted for reciprocal 'movement within the sleeve member 3. and is provided at its lower end with a suitable packing I3, whichmay serve as a piston head. The packing I3 is shown secured to the lower end of the piston I3 by a valve member 2I, having a threaded extension received in threaded engagement with the threaded socket provided in the piston I3, as best shown in Figures 3 and 4. The member 2| has a cone-shaped valve face 22 i adapted to engage a conical seat 23 provided in the lower portion of the sleeve member 3. The seat 23 surrounds a fluid passage 24 provided in the lower end of the sleeve member 3.

The valvemember 2I is shown provided with a depending stem 25 which is relatively smaller in diameter than the passage 24 in the lower end oi' the sleeve member 3. whereby it may pass freely through said opening and through the discharge port I4, into engagement with the check valve I1, thereby to unseat said valve, as shown in Figures 3 and 4. The diameter of the discharge passage I4 is preferably substantially the same as the diameter oi' the iluid passage 24 provided in the bottom of the sleeve member 3.

The overall length of the sleeve member 3 is slightly less than the overall length of the interior of the cylinder 3, and is adapted for limited sliding movement therein, asbest shown in-Figures l, 2, and 3.

The upper or projecting end portion of the piston I3 is shown provided with a notch or recess 23 adapted to receive a pin 2l, shown provided in an operating handle 23, which may be pivotally secured to the casing 3 of the jack,

In the operation of this novel jack, the reservoir 1 is provided with a quantity oi inelastic duid, such for example, as oil. 'I'his oil is pumped from the reservoir into'the chamber I3 below the plunger 5 oi the jack, whereby the plunger or ram 3 is moved upwardly in the cylinderv 4. The circulation oi' the fluid to and from the chamber I3 is accomplished entirely by manipulation of the pump handle 23.`

When the pump handle 23` is moved upwardly, the sleeve member 3 is moved upwardly as a result of its irictional engagement with the piston I3, particularly the packing I3, until its upper end engages an abutment v3I provided at the upper end of the pump cylinder 3. A suitable packing 32 and packing nut 33 are shown provided at the upper end oi the pump cylinder 3 'to prevent leakage yof the iluid around the upper end oi'. the piston I3. .When the sleeve member 3 is moved upwardly into engagement with the abutment 3l, vas above stated, its lower end moves out `of engagement with the seat I2 and the stem 23 of the piston valve member 2| is then also withdrawn` from the iluid passage 24 in the lower end of the sleeve member 3.

lContinued upward movement of the piston I3 creates a vacuum in the intake e I 3, whereby fluid is drawn from the reservoir 'I through the intake passage I3 and fluid passage 24 in the sleeve member 3, and into the interior of the sleeve member.

When the movement oi the pump piston I3 is reversed, the iluid within the sleeve member is put under pressure, whereby the pressure exerted against the inner conical surface 34 of the sleeve member 3 and the seat 23 thereof will cause the sleeve member to move downwardly. Such downward movement of the sleeve member may also be assisted by the irictional engagement of the packing I3 of the pump piston I3, with the wall of the sleeve member.

Thus, upon initial reverse or downward movement of the pump piston I3, the lower end of the sleeve member 3` moves into engagement with the valve seat I2, and thereby prevents the duid drawn into the sleeve member from returning to the reservoir 1. The iiuid within the sleev member is then forced through the duid a 1 -1e 24 in the sleeve member, and through the discharge passage I4 into engagement with the check valve I'I. whereby said check valve is unseated, as shown in Figure 2, thereby permitting the pumped fluid to now through the passage Il and into the chamber I3 below the plunger or yram l of the jack', whereby said plunger is elevated. Upon the up-stroke of the pump piston I3, the vacuum created within the sleeve 3, assisted by the irictional engagement of the packing I3 oi the pump piston I3 with the wal.i ot the sleeve member 3, will cause the latter to the stem` 25 of the valve member 2 I.

move upwardlywith the pump piston, until Ithe upper end thereof engages the abutment 3|. The check valve I1 then engages its seat, whereupon iluid is' again drawn -into the sleeve member through the intake port Il, as hereinbefore described. It will thus be seen that the sleeve member 9 serves as a check valve to prevent the iluid drawn into the sleeve member from return-4 ing to the reservoir 1, during the down stroke of the pump pistony IQ, and also as a cylinder for the pump-piston Il.

To release the flil'id from the Jack cylinder 4 to permit the lifting head l to return to its normal lowered position, the pump piston I8 is moved downwardly to the position shown in Figure .3. When in this position, the check valve Il 'is unseated, because of its engagement with When thus positioned, the valve face 2'2 of the member 2l is engaged with the valve seat 23 within'the sleeve member 9, whereby the iluid within the member.

discharge passage Il of the pump,A which iluld is under pressure as a result of the weight of the load, when the check valve I'I is open, cannot enter the interior of the sleeve member` 8. The operator then slowly retracts or raises the pump. cylinder I8, by manipulation of the operating handle 28, until the sleeve member! reaches substantially the position shown in Figure 4, or, in other words, until a small gap II is provided be;

tween the valve seat I2 and the lower end of the sleeve member i, as shown in Figure 4. When the sleeve member I is thus positioned, the fluid in the chamber Il is released and returns to\\.

the reservoir 'I through the passages I5 and Il,

' as wm readily ,be understood; It will thus be Seen that the entire operation of the pump? is controlled -by manipulation ot the operating handle 28, which greatly simplifles ythe operation of operating the jack or other device to be'operated.

In the accompanying drawing. I have shown- `the invention as applied to a conventional form.

of hydraulic jack, but it is to be understood that it may be applied to various other devices and apparatus, wherev applicable, without departing from the scope of the invention.

I claim as my invention: 1. A nuid pump comprising a cylinder having an intake, a reservoir connected with the intake.

`said' cylinder lalso. having a discharge passage provided at one end with .a seat, a spring-actuated check valve normally closing the opposite end of said passage. a sleeve mounted inthe cylinder and adapted. for limited axial movement therein, one end of said sleeve being adapted to engage said seat to close the intake, a piston operable within the sleeve 'and adapted to move said sleeve out of engagement with'said seat upon the suction stroke oi the piston. said sleeve having an opening in one end whereby iiuid f drawn from the reservoir through the intakeis drawn into the sleeve upon each suction stroke of the piston, said sleeve being movableinto engagement with said seat when the piston commences its pressure stroke, whereby iuid inthe sleeve is forced therefrom through the discharge passage, and meansV carried by the piston adapted to engage and unseat the check valve when the piston approaches the bottom of its stroke, said sleeve and piston being so related that when into the sleeve is -forced through the discharge' passage, a valve carried by the piston adapted 3 sage te the reservoir without entering the' sleeve 2. A iluid pump comprising a cylinder having an intake, a fluid reservoir in connection with the intake, said cylinder valso having a discharge I passage provided at one end with a conical seat. aspring-actuated valve normally closingthe -opposite end of saidpassage, a sleeve member mounted for limited sliding movement vwithin the cylinder and having a conical end adapted to engage said seat, thereby to close the intake, said conical end having an-opening therein alined with said discharge passage, a valve seat surrounding said opening, a piston operable within the sleeve and having a valve membersecured thereto and adapted to engage the valve'seat in the sleeve member, said valve member having a stem adapted to engage and unseat the check valve when the piston is at the limit of its pressure stroke and whereby said valve member will engage the seat within the sleeve to prevent the entrance of iluid into the sleevemember when the check valve isactuated to permit the ypumped fluid to return to the reservoir, said sleeve member being adapte to be moved out of engagement with said lseat upon initial return movement of the piston and before the check valve engages its seat, whereby the discharge passage lower end, a piston operable in the sleeve to draw fluid through the intake into the sleeve upon the suction stroke of the piston, said sleeve being actuable to close the intake upon the pressure stroke of the piston, whereby the -iluid drawn to close the uid passage in the sleeve when the Piston is at the bottom of its pressure stroke,

said valve'having a stem adapted to be projeoted through the fluid passage in I'the sleeve and to engage andunseat the `check valve, when the Piston is at the bottom of its pressure stroke, saidpiston and sleeve being so related that when the movement of the piston is slightly reversed, after the check valve has mn unseated, the sleeve is operated. to open the intake without unseat'ing said val ve. whereby theV pumped uid may return to the reservoir without entering the sleevemember.

4; In a device of th@ class described, a cylinder having an intake, a reservoir connected with the' intake, said cylinder also having a discharge passage, a check valve inthe discharge passage, a sleeve member -mounted for axial movement in the cylinder and having a conical end portion adapted to close the intake when the sleeve is at one end of its stroke, the conical end. of said sleeve member having a. fluid passage thereinadapted to communicate with the discharge passage when the sleeve member is positioned to the piston has been moved to the bottom .of its stroke to unseat the check valve 'and its movement is slightly reversed, the sleeve member is moved out of engagement with said seat.'where by the fluid may return from the discharge pasclose the intake, a piston (movable within lthe sleeve member and having a valve adapted to close the huid passagegn the bottom oi the sleeve when the piston is'at the bottom of its pressure stroke, said valve having a stem' adapted to engage and unseat the check valve when the piston is at the bottom of its stroke, and the frictional connection-between the piston and said sleeve member being such that when the piston is positioned to open the check valve and is slightly reversed, the sleeve member is operated to open the intakewithout unseating said valve, whereby the pumped fluid may return to the reservoir without entering the.sleeve member.

5. A uid circulating pump comprising a cylinder having an intake, a reservoir connected with the intake, said cylinder also having a discharge passage axially alined with the cylinder, said discharge passage having a seat at one end. a check valve normally closing the opposite end f said passage, a sleeve mounted for limited 15 axial movement in the cylinder and having a :luid circulating passage in its lower end, piston in the sleeve, the lower end of said sleeve being adapted to engage said seat and close the intake upon the pressure stroke of the piston. whereby fluid in the sleeve may be pumped through the valve controlled discharge passage.

and valve. means carried by the piston adapted to engage and unseat the check valve to permit return flow of the fluid to the reservoir, said valve means also operating to close the uid circulating passage in the sleeve to prevent the pressure-duid from entering the sleeve during return tlow of thefuid to the reservoir.

HAROLD NJISON. 

